Manchester City striker Sergio Aguero feels confidence has been restored at the Etihad Stadium and the champions can finish the season strongly.

City's hopes of retaining their Barclays Premier League title may appear slim but Aguero says they are determined to go down fighting.

Aguero and his team-mates produced the perfect response to their damaging - and dismal - surrender at Southampton just over a week ago by brushing aside npower Championship outfit Leeds in the FA Cup.

The Argentinian struck twice as City powered into a quarter-final tie against Barnsley with a 4-0 win at Eastlands.

Attention now switches back to the league with City trailing rivals Manchester United by 12 points, with 12 games remaining, ahead of Sunday's clash against third-placed Chelsea.

Aguero told City TV: "This helped us to do things well and give us confidence for the Chelsea game.

"It will be a good match, difficult, but obviously we need to go out and win.

"I think against Southampton none of us played well and it was a bad day for us all - an error which we hope not to repeat.

"We will try not to lose any more points in the league so we can keep all three points.

"I think we've played well and reached the next round. We need to continue like this."

City outclassed a Leeds side who continue to labour in pursuit of a play-off place in their own division.

The result did not seem in doubt after Yaya Toure combined with David Silva and Carlos Tevez before opening the scoring after just five minutes.

Aguero quickly added the second from the penalty spot after he was deemed to have been pulled back by Tom Lees and created the third for Tevez early in the second half.

Aguero wrapped up the win when he clipped a well-weighted ball from Silva beyond Jamie Ashdown and in off the post 16 minutes from time.

City might have had several more. Substitute Jack Rodwell went closest to adding to the tally when he headed against the bar.

The build-up to the game had been dominated by fresh speculation over manager Roberto Mancini's position in the light of the Southampton capitulation.

But City fans made clear their support for the Italian, who is now eyeing a repeat of the 2011 FA Cup success.

Aguero said: "It was a very good game for us. We are happy with the win and reaching the next round of the FA Cup.

"We played well - from the start we gave it our all. We had spoken about having to give our all in the first 15 minutes.

"The truth is we played a great game and we hope we can continue to do so constantly."

Aguero himself has had a frustrating second season at City, having been curtailed at times by knee and hamstring injuries, but now has 13 goals for the season and looked in fine form.

The 24-year-old, a club record £38million signing two years ago, said: "Yes, I had a great game. The whole team played well though.

"The important thing was to win and we did. So now we will have a bit of calm and can concentrate on the Chelsea game.

"Yes, they were two good goals but the most important thing was they helped us to win. So I'm happy for the goals and for the win.

"I really like this cup, played as a single leg. Obviously if we maintain our concentration, I think we have a team that can reach the final."

Mancini, who made clear he was not fearing for his position prior to a game billed as vital for his future, intends to carry on fighting on both fronts.

He said: "I had a negative energy after Southampton but I am happy after this game.

"I wanted a response after Southampton and we played well. Now it is important we continue."

"We are a top team. If we lose an important game we should continue to work hard. In football it is never finished."

While Mancini was defiant, his Leeds counterpart Neil Warnock was almost resigned to his fate.

Leeds are eight points off the play-off positions and Warnock, in the final months of his contract, accepts he will not be staying at Elland Road if he does not achieve promotion.

But he is not going to throw in the towel and, with a game to come on Wednesday, said: "I'd love to beat Blackpool and then go to Blackburn - who are on a high after beating Arsenal - and have a go at them.

"Let's see if we can get seven points from the next three games. That would take us on."